Amazon Web Services is expected to have revenue of $3.8 billion in 2013 and could be worth $19 billion to $30 billion if it were a standalone company, argued Macquarie Capital analysts in a research note.

Macquarie's argument, led by analyst Ben Schachter, relies on the addressable market for cloud computing and the assumption that AWS accounts for all of Amazon's growth in the "other" revenue category.

The Macquarie research note landed at the same time as a Morgan Stanley upgrade. Scott Devitt upgraded Amazon based on international growth and global fulfillment services. Devitt called AWS a strategic asset.

Schachter's report on AWS was far more interesting. Schachter said that AWS is likely to land more large enterprises, a reality that is likely to boost growth. To date, AWS has relied on startups and small companies. The large company argument adds up. At AWS' customer and partner powwow last year, companies like Pfizer were readily available.

Independently, I've confirmed the profile of one U.S. sales region for AWS. In a nutshell, this region features top 200 accounts that range from $5,000 a month to about $200,000 a month. If you extrapolate those numbers throughout the U.S., combine international markets and smaller accounts paying about $1,000 a month it's clear that AWS has some serious growth ahead. That growth can come from additional partnerships and better channel efforts alone.

Macquarie's Schachter is estimating that AWS' current addressable market was $11 billion in 2012 and the unit delivered actual revenue of about $2 billion. In 2013, Schachter estimates that AWS will have revenue of $3.8 billion.

Among the key points from the Macquarie report:

AWS is 100 percent gross margin business for Amazon. Amazon's AWS costs run through its technology and content expense line. As AWS grows faster than Amazon's retail business, the gross margin profile for the entire company changes.

Storage growth for AWS' S3 services is exponential and can carry growth for years.

AWS is expected to have revenue of $3.8 billion in 2013, $6.2 billion in 2014 and $8.8 billion in 2015. In 2015, AWS will be 7 percent of Amazon's revenue---significant, but not large enough for the retailer to be required to break out numbers in its financial reports.

Comparisons to AWS are tricky since RackSpace is among the only standalone direct competitors. Savvis and Terremark compete with AWS, but those outfits are subsidiaries of CenturyLink and Verizon, respectively.

Schachter said:

Using our estimate of $3.8bn for 2013 AWS revenues, and applying a ~5x multiple based on the comps noted above, we arrive at a valuation of ~$19bn for the business on an EV/Sales basis (equating to ~$41/share of AMZN stock). Importantly, we believe this to be a conservative valuation multiple, as AWS revenues are growing much faster than any of the comps incorporated above. At an 8x valuation multiple, we estimate the AWS business could be worth $30bn as a stand-alone company, or ~$66/share.